Digital BW, The Print

I somehow fried my 256 mb flash card in my Canon G2.  I worked when I 
took the pictures but when I got home the camera told me that there 
was a card error and my card reader did not recognize the disk.  I 
have taken it through carry-on X-ray a number of times and cannon 
beleive that was the problem.  I would like to know what I did as 
these are not cheap and I would prefer not to do it again.  Any ideas 
appreciated.  As this really is off-topic please contact me at 
kobrins@....

Thanks,

Steve